Chance in daily events: the language of likelihood

Welcome to the World of Chance!

Have you ever wondered if it will rain during recess, or if you will win a game of "Rock, Paper, Scissors"? In Mathematics, we call this Chance. Exploring chance helps us describe how likely it is that something will happen in our daily lives. We use special words to talk about these events so we can share our ideas clearly with others.

In this chapter, we are going to learn the language of likelihood. This is part of our work in Data Handling, where we look at information and make sense of the world around us.

Phase 1: The Three Big Words

When we first start talking about chance, we use three main words to describe an event. Think of these as the "starting blocks" for understanding likelihood.

1. Impossible
This means there is no way the event can happen. It is simply not possible.
Example: It is impossible for a cat to turn into a dragon. It is impossible to pick a blue marble out of a bag that only has red marbles.

2. Maybe
This means the event might happen, but we aren't sure. It could go either way!
Example: Maybe it will snow tomorrow. Maybe you will have pasta for dinner tonight.

3. Certain
This means the event will definitely happen. There is no doubt at all.
Example: It is certain that the sun will rise tomorrow. It is certain that after Monday, the next day will be Tuesday.

Quick Review: Phase 1

• Impossible: Can't happen.
• Maybe: Might happen.
• Certain: Must happen.

Phase 2: Adding More Detail

As we become experts at describing chance, we need more "in-between" words. Sometimes "maybe" isn't specific enough. Is it a strong maybe or a weak maybe? To help with this, we add two more phrases:

Less Likely

This is a type of "maybe" where the event could happen, but it probably won't. The chances are small.
Example: It is less likely that you will find a four-leaf clover in the grass than a three-leaf clover. It is less likely to rain in a desert than in a rainforest.

Most Likely

This is a type of "maybe" where the event probably will happen, but it isn't a 100% guarantee.
Example: Since you practiced every day, it is most likely that you will do well in your piano recital. If there are 10 apples and 1 orange in a bowl, it is most likely that you will pick an apple if you close your eyes.

Remember: These words help us compare events. For example, if you are looking at a bag of 50 blue blocks and 2 red blocks, picking a blue block is most likely, while picking a red block is less likely.

The Likelihood Scale

Imagine a line. On one end, we have Impossible. On the other end, we have Certain. All our other words fit somewhere in the middle!

Impossible \(\rightarrow\) Less Likely \(\rightarrow\) Maybe \(\rightarrow\) Most Likely \(\rightarrow\) Certain

Analogy: Think of a volume knob on a radio. Impossible is like the volume being at \(0\). Certain is like the volume being all the way up. The other words describe how "loud" the chance is!

Using Chance in Daily Life

We use the language of likelihood every day without even realizing it. Here are some inquiry questions to think about:

• Is it certain or most likely that you will come to school tomorrow?
• Why is it impossible to roll a \(7\) using a standard six-sided die?
• Is it less likely or most likely that you will see a bird today?

Note: Talking about chance is closely related to how we organize data. You might remember learning about Sorting and labelling objects by attributes; we use those same sorting skills to help us decide which chance word to use!

Tips for Success

Don't worry if this seems tricky at first! Deciding between "maybe" and "most likely" can sometimes depend on what you know about the situation. Here is how to stay on track:

1. Look for Evidence: If you are deciding if rain is "most likely," look at the clouds! If the sky is dark and grey, "most likely" is a great choice.
2. Be Careful with "Certain": Use the word "certain" only if there is absolutely no other choice. If there is even a tiny, tiny chance it won't happen, use "most likely" instead.
3. Use your own words first: It's okay to start by saying "No way!" (Impossible) or "Probably!" (Most Likely) before moving to the official math words.

Key Takeaways

• Chance is the language we use to describe how often events might happen.
• We use Impossible for things that cannot happen.
• We use Certain for things that must happen.
• We use Less Likely, Maybe, and Most Likely to describe everything in between.

Did you know? Even though we use these words in Math class, scientists and weather forecasters use them every single day to help people prepare for the future!